The present invention relates to a brake control method of a reel motor in a tape recording/reproducing apparatus, particularly to a method for providing an even tape tension during braking of reel motors.
Generally, the moment of inertia of a rotating body as shown by FIG. 1 is directly proportional to the mass and radius of the rotating body. This relationship can be represented as follows; EQU MI=(1/2)MR.sup.2 ( 1)
where,
MI: moment of inertia of the rotating body PA1 M: mass of the rotating body PA1 R: radius of the rotating body.
The above moment of inertia of the rotating body is also applicable to the reel of the tape recording/reproducing apparatus. That is, in the case that the tape is being rolled up on the reel, the reel will have the moment of inertia with a value determined by the above formula (1).
FIGS. 2A and 2B illustrate the tape being wound on the reels. In FIG. 2A, the amount of the tape wound on a supply reel is more than that on a take-up reel. In this state, if the two reels are simultaneously stopped with equal force, the tape will become loose, because the moment of inertia of the supply reel is greater than that of the take-up reel.
On the other hand, in the case that the amount of the tape wound on the take-up reel is more than that on the supply reel as shown in FIG. 2B, if the two reels are simultaneously stopped with equal force, the tape will become tight, because the moment of inertia of the take-up reel is greater than the supply reel. That is, if the rotating two reels are stopped in a state that the amounts of tapes of the supply reel and the take-up reel are different, the tape becomes loose or tight since the moment of inertia differs between the two reels.